Electron beam annealing apparatus and annealing methods using the same

CROSS-REFERENCE TO RELATED APPLICATIONS

0001This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2008-0127268, filed on Dec. 15, 2008, in the Korean Intellectual Property Office (KIPO), the entire contents of which is incorporated herein by reference.

BACKGROUND

00021. Field

0003Example embodiments relate to electron beam annealing apparatuses and annealing methods using the same.

00042. Description of the Related Art

0005After a thin layer is deposited on a substrate an annealing process is usually performed on the deposited thin layer. An annealing process refers to activation of the thin layer by heating the substrate on which the thin layer is deposited. Using an annealing process, a silicon thin layer may be recrystallized, impurities in a metal thin layer may be removed, and/or oxygen required in an oxide thin layer may be supplied.

0006An annealing process that is performed on a deposited thin layer may be classified into thermal annealing and laser annealing. In thermal annealing, a substrate on which a thin layer is deposited may be heated to activate the thin layer. However, in thermal annealing, the substrate may be required to endure high temperature processing. In laser annealing, a pulsed laser may be scanned onto a substrate to locally heat desired regions of the deposited thin layer on the substrate in order to activate a thin layer. However, in laser annealing, a thin layer functioning as a heat reservoir may be required under the thin layer that is to be activated in order to absorb laser energy and when a large-sized substrate is used, the amount of optical equipment for laser focusing may be increased, thereby increasing the costs. Additionally, the deposited thin layer may be deformed.

SUMMARY

0007Example embodiments include electron beam annealing apparatuses and annealing methods using the electron beam annealing apparatuses.

0008Example embodiments include an electron beam annealing apparatus including an electron beam scanning unit configured to scan a pulsed electron beam onto a substrate during an annealing process.

0009According to example embodiments, the apparatus may include a chamber configured to mount the substrate including a thin layer that is on the substrate and to supply a reaction gas. The apparatus may include a reaction gas delivery unit configured to continuously supply a uniform amount of the reaction gas to the chamber during an annealing process. The chamber may be configured to mount the substrate including a deposited thin layer that may be a reductive thin layer. The reaction gas delivery unit may be configured to supply the reaction gas that may include H₂and/or NH₃. The chamber may be configured to mount the substrate including a deposited thin layer that may be an oxide thin layer. The reaction gas delivery unit may be configured to supply the reaction gas that may include O₂or N₂O. The apparatus may further include a bias applying unit configured to apply a bias voltage to the substrate. The bias applying unit may be configured to continuously apply a bias voltage to the substrate during an annealing process.

0010Example embodiments include an electron beam annealing method including scanning a pulsed electron beam onto a substrate.

0011The method may include supplying a reaction gas into a chamber including the substrate. A uniform amount of the reaction gas may be continuously supplied to the chamber during an annealing process. The method may include applying a bias voltage to the substrate. The bias voltage may be uniformly and continuously applied to the substrate during the annealing process.

BRIEF DESCRIPTION OF THE DRAWINGS

0012Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings. <figref idref="DRAWINGS">FIGS. 1-5</figref> represent non-limiting, example embodiments as described herein.

0013<figref idref="DRAWINGS">FIG. 1</figref> is a schematic view illustrating an electron beam annealing apparatus according to example embodiments;

0014<figref idref="DRAWINGS">FIG. 2</figref> is a graph of electron beam pulses as a function of time according to example embodiments;

0015<figref idref="DRAWINGS">FIG. 3</figref> is a graph of bias voltage as a function of time according to example embodiments;

0016<figref idref="DRAWINGS">FIG. 4</figref> is a scanning electron microscope (SEM) image of a laser annealed silicon thin layer; and

0017<figref idref="DRAWINGS">FIG. 5</figref> is a SEM image of an electron beam annealed silicon thin layer according to example embodiments.

0018It should be noted that these Figures are intended to illustrate the general characteristics of methods, structure and/or materials utilized in certain example embodiments and to supplement the written description provided below. These drawings are not, however, to scale and may not precisely reflect the precise structural or performance characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values or properties encompassed by example embodiments. For example, the relative thicknesses and positioning of molecules, layers, regions and/or structural elements may be reduced or exaggerated for clarity. The use of similar or identical reference numbers in the various drawings is intended to indicate the presence of a similar or identical element or feature.

DETAILED DESCRIPTION

0019Example embodiments will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. Example embodiments may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those of ordinary skill in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals in the drawings denote like elements, and thus their description will be omitted.

0020It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Like numbers indicate like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items.

0021It will be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

0022Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

0023The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

0024Example embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle may have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation takes place. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.

0025Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly-used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

0026<figref idref="DRAWINGS">FIG. 1</figref> is a schematic view illustrating an electron beam annealing apparatus according to example embodiments. Referring to <figref idref="DRAWINGS">FIG. 1</figref>, the electron beam annealing apparatus <b>100</b> may include an electron beam scanning unit <b>130</b>. The electron beam scanning unit <b>130</b> may include, for example, a plasma generating reactor, a first lens extracting desired electrons from the plasma, and a second lens focusing electron beams that have passed through the first lens. However, the electron beam scanning unit <b>130</b> is not limited thereto. The electron beam scanning unit <b>130</b> may scan an electron beam onto a region of a substrate <b>120</b>. The substrate <b>120</b> may be in a chamber <b>110</b> and a thin layer <b>121</b> may be on the substrate <b>120</b>. The thin layer <b>121</b> may be, for example, a deposited thin layer.

0027<figref idref="DRAWINGS">FIG. 2</figref> is a graph of electron beam pulses as a function of time according to example embodiments. Referring to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, the electron beam scanning unit <b>130</b> may scan electron beam pulses onto the substrate <b>120</b> to anneal the thin layer <b>121</b>. When a substrate <b>120</b> is continuously scanned by an electron beam for the purpose of annealing, electrons may build up on the thin layer <b>121</b> and the deposited thin layer on the substrate <b>120</b> may be heated to an excessive temperature. In order to prevent or reduce excessive substrate heating, according to example embodiments, the electron beam scanning unit <b>130</b> may scan electrons using electron beam pulses rather than a continuous electron beam. When electron beam pulses are scanned onto a desired region of the substrate <b>120</b> by the electron beam scanning unit <b>130</b>, the deposited thin layer on the substrate <b>120</b> may be heated to an anneal temperature, thereby activating the material of the thin film <b>121</b>. The anneal temperature may be predetermined.

0028According to example embodiments, a reaction gas may be supplied to the chamber <b>110</b> during the annealing process. A uniform amount of the reaction gas may be continuously supplied to the chamber <b>110</b> during the annealing process from a reaction gas delivery unit. The reaction gas delivery unit may supply reaction gas, for example, via GAS IN. The reaction gas may be radicalized by scanned electrons of the electron beam scanning unit <b>130</b> and may improve the activation process of the thin layer <b>121</b>. When the thin layer <b>121</b> is a reductive thin film (e.g., a metal thin film) the reaction gas may contain, for example, H₂or NH₃. When the layer <b>121</b> is an oxide thin layer (e.g., a silicon oxide thin layer) the reaction gas may contain, for example, O₂or N₂O.

0029The electron beam annealing apparatus <b>100</b> may include a bias applying unit <b>140</b> that may apply a bias voltage to the substrate <b>120</b>. The bias voltage may induce electron beams onto the substrate <b>120</b>. <figref idref="DRAWINGS">FIG. 3</figref> is a graph of bias voltage as a function of time according to example embodiments. Referring to <figref idref="DRAWINGS">FIGS. 1 and 3</figref>, the bias applying unit <b>140</b> may continuously apply a uniform bias voltage to the substrate <b>120</b> during the annealing process.

0030A method of annealing will now be described with reference to <figref idref="DRAWINGS">FIGS. 1-3</figref>. A thin layer <b>121</b> may be deposited on a substrate <b>120</b>. The substrate <b>120</b> including the thin layer <b>121</b> may be mounted in a chamber <b>110</b> of the electron beam annealing apparatus <b>100</b>. A pulsed electron beam may be scanned onto and/or across a desired region of the substrate <b>120</b> using the electron beam scanning unit <b>130</b>. A uniform amount of a reaction gas may be continuously supplied to the chamber <b>110</b>. A uniform bias voltage may be continuously applied to the substrate <b>120</b> by the bias applying unit <b>140</b>. The substrate <b>120</b> may be heated to an anneal temperature by the annealing process and the material of the deposited thin layer <b>121</b> on the heated substrate <b>120</b> may thereby be activated.

0031<figref idref="DRAWINGS">FIG. 4</figref> is a scanning electron microscope (SEM) image of a laser annealed silicon thin layer. Laser energy may be used for localized heating of a substrate in a laser annealing method. However, when a thin layer is melted by a laser, seeding may be generated in a low temperature area of the melted thin layer prior to recrystallization and the thin layer may be prone to deformation. As illustrated in <figref idref="DRAWINGS">FIG. 4</figref>, when a silicon thin layer is recrystallized using a laser annealing method a surface of the thin layer may become rough.

0032<figref idref="DRAWINGS">FIG. 5</figref> is a SEM image illustrating an electron beam annealed silicon thin layer according to example embodiments. H₂may be used as a reaction gas supplied to the chamber. In the electron beam annealing method according to example embodiments, silicon bonds may be broken by the energy of electrons and uniform rearrangement of the silicon bonds may be achieved in the thin layer. Accordingly, recrystallization of the thin layer may be induced with minimized or reduced deformation of the thin layer. As illustrated in <figref idref="DRAWINGS">FIG. 5</figref>, when a silicon thin layer is recrystallized using an electron beam annealing method according to example embodiments, the surface of a thin layer may be smooth.

0033According to example embodiments, a pulsed electron beam of an electron beam annealing apparatus may be scanned onto a substrate in order to activate a thin layer on the substrate. In order to improve the activation process, a reaction gas may be supplied into a chamber of the electron beam annealing apparatus and/or a bias voltage may be applied to the substrate. Electron beam annealing to activate a thin layer may prevent or reduce damage to either the thin layer and/or the substrate.

0034While example embodiments have been particularly shown and described, it will be understood by one of ordinary skill in the art that variations in form and detail may be made therein without departing from the spirit and scope of the claims.